But the CFA being pegged to the euro, means that the countries adopting it can't really do monetary policy, like countries in the eurozone can't
The two CFA franc zones have zone central banks (which aren't exclusively controlled by countries in the respective zone, since France has a seat on each), it's not individual national central banks issuing currency or managing the peg.
Like Zimbabwe did.
>Food production halved in the 1990s as a result of [Mugabe's] decision to strip white farmers of their land and hand it to members of the black population who, in many cases, had no farming experience.
before the inflation kicked off. https://news.sky.com/story/how-zimbabwes-economy-has-collaps...
Same brilliant policy in Venezuela pretty much.